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i Sheets-Sheet 1. P. H. JACKSON. BUILDING AND BRIDGE GONSTRUOTI Patented*y ot. 18, 1887.

N. Pneus. vlmmumumpw. wan-mm. nc,

(No Model.) 2 Sheets-Sheet 2IV l P. H. JACKSON. Y BUILDING AND BRIDGEGUNSTRUGTION.

Patented Oct. I8

If`1q12.

N. PETERS. PhowLnhogmpher. washingmn, C'4 C.

- Unirse raras PATENT FFlCEO PETER H. JACKSON, OF SAN FRANCISCO,CALORNIA.

BUILDING; .AND BRIDGE CONSTRUCTION.

SPECIFICATION orrning part Of Letters Patent No. 371,843, dated October18, 1887.

Applmition iilrd January "l, i886.

Serial No. 157,930. (No model.)

- the city and county of San Francisco, and

vIO

State of California, have invented an Improvement in Building and BridgeConstruction; and I hereby declare the following to be a full, clear,and exact description thereof, sufficient to enable any person skilledin the art to which my invention belongs to make and use the same,reference being had to the accompanying drawings, forming part of thisspecification.

This Ainvention relates to'girders, bridges, buildings, sidewalks havingvaults or chambers vbeneath them, Sie.

The object is to strengthen bridges, buildings, Ste., in theconstruction of which concrete, artificial stone. brick.l anf'icement ormortar, or similar materials, are largely employed, and at the same timeemploy a proportionally small quantity of metal, dispensing with thelarge and costlymctal beams and girders now employed, and thusdecreasing materially the cost of construction, while increasing thestrength and security of the structure.

With these objects in View my invention consists, broadly, in buildinginto the lower part ofthe body of cement, artificial stone, or similarmaterial, the part below the neutral line, which is subjected to tensilestrain when the bridge, floor, orst'ructnre is loaded,asmallmetallici-shaped beamer beams, cemented to l.the surrounding material,which beam makes up the-deficient tensile strength of the body in whichit is embedded.

Furthermore, the invention consists in employing the materials of theconstruction or body to aid in its own support; furthermore, in meansfor sustaining the ends ofthe structures, as in bridges, iloors,sidewalks, roofs, and the like platforms-oi:- tnesc materials, Whetherconstructed in'whole or in divisions or sections, in iiat sections or inarches, cmploying the material of the platform or body to resistcompressive force and the longitudinal supporting tie or ties resistingthe tensile strain.

Furthermorethe invention consists in arranging the flanged metal ties inthe lower part of the door, bridges, Ste., below its neutral line,parallel with one another and in the same horizontal plane, so that whena load rests on the body between two parallel flanged beams and the archis thereby deflected the direction of thrust of the material will beagainst 'the facing sides of the said beams at an upward angle, (asindicated by the dotted lines and arrows in Figs, 10 and 11,) comparedto the direction before deflection took plaee,and the upper flanges ofthe beams, beneath which the material rests, operate to hold thematerial between the beams and prevent it from slipping over or beingforced over them; and, inall y, in securing to the small beams or to a[iat bar near each of its ends and above its neutral line uprightresistance-plates, which, when the beam is embedded ,in the structurebelow the neutral line thereof, will resist the extension of thesnrronmling material.

Bridges, floors, sidewalks, girders, and the like made of cement, artiiieial stone, concrete, or similar material possess the property ofgreat resistance to compression or crushing, but are comparatively veryweak in resisting tension or a force tending to separate or destroy thecohesion of the particles; and to furnish the required strength of thisweak part to equalize the great compressive resisting property of thematerial above the neutral axis, I employ these small metallic ilangedbeams, built in the weak part of the body, so,

that the structure may be oi" uniform strength in resisting tension andcompression.

All structuressuch as sidewalks with vaults beneath them, floors withchambers below them, beams and girders, bridges, and the like-aresubjected to transverse strain, caused by loads or weight on their tops,and have to .resist compression on their upper parts above the neutralline and tension below their neutral line, the line where these twoforces of diametrieallyopposite character meet and neutralize each otherlying half-way between the top and bottom of the body, and being hereindenominated the neutral line.

In the accompanying drawings, in which like letters of referenceindicate corresponding parts, Figures 1 and 2 are longitudinal verticalofthe surrounding material.

sectional views illustrating the action of forces, and adapted in thatrespect to a. bridge, sidewalk, floor, beam, girder, or any suchstructure, resting on end supports and adapted to be loaded andsubjected to transverse strain, Fig. 1 representing the structure whenthere is no load upon it, and Fig. 2 representing it deflected under theweight of the load L, the vertical imaginary lines cfcfin Fig. 1 beingchanged when the structure is deilected into radial lines, as shown inFig. 2, .fr y in both views representing theneutral line,where thecompressive and tensile forces neutralize each other. Fig. 3 is alongitudinal vertical sectional view of a bridge, sidewalk, girder, orlike structure, resting on end supports, with a small metallic iangedbeam built in longitudinally and cemented to the surrounding materialbelow its neutral axis, acting as a resistant to the tensile strain.Fig. 4 is a crosssectional view of a structure similar to that shown inFig. 3, showing the small metallic flanged beams embedded and cementedin a hat body of the cement or concrete or like material. Fig. 5 is across-sectional view showing the small flanged metallic beam embedded atthe foot of an arch and cemented to the surrounding material. Fig. 6 isa longitudinal vertical sectional view of a bridge, sidewalk, girder, orsuch structure, resting on end supports and constructed in the usualmanner, with a large metallic beam built in the material and adapted tocarry the entire load by resisting both the compressive force andtensile strain. Fig. 7 is a cross-sectional view of a structure similarto that shown in Fig. 6, showing the large beam inclosed in a dat bodyFig. 7"isacrosssectional view showing the large beam inclosed at thefoot of an arch which it supports. Fig. 8 is a longitudinal verticalsectional view of a. bridge or like structure, showing a small beam orflat bar embedded .therein beneaththe neutral line of the structure,having fastened to it near each of its ends and above its neutral line aresistance-plate, d. Fig. 8 is an enlarged view of the right-handportion of Fig. 8, showing more plainly one ol' the resistance-platesand the position and manner in which it is attached upon the beam orbar.Fig. 9 is a longitudinal vertical sectional view of a bridge or likestructure of cement, artitlcial stone, or similar material, in which mysmall ianged beam is embedded below the neutral line x y, but notcemented to the surrounding material, the bridge being shownconsiderably deflected under the heavy load L, so that the beam a isshortened above its neutral line g h, shortening to the greatest extentat its top, while the structure is lengthened-'below its neutral line xy, this view illustrating the action of the two forces without therestraintof unity between the beam and structure. Figs. 'l0 and 11 arevertical crosssectional views of a bridge or other structure having mysmall metallic `illanged beams embedded and cemented-in the footings ofthe arches, vbelow the neutral lines of the arches and parallel to oneanother, the arches being shown dede( P:ed'by the f.; aight of loads L,and the directionof thrust against the facing sides of the beams of thearch on which the weight is resting being then at a slightly-upwardanwhile the remainder is made in sections. Fig. 8

13 is a perspective view of a bridge, sidewalk, or likestructure,resting on end supports and covering an open space or chamber,and con sisting of lat sectional arches having flanged metallic beamsembedded in the supportingsections below their neutral line, andsupported at their ends by longitudinal non-.embedded ties. Fi 14 isperspective view of a bridge, sidewalk, or like structure, resting onend supports and covering an open space beneath, and consisting of abody of cement, artificial stone, or the like, havinga flat'upper anddat lowersurface,having small flanged. metallic beams embedded in itbelow its neu'- tral line, the ends of t-hese embedded beams beingsupported on and secured to longitndix nal non-embedded ties.l

All structures-such assidewalks with vaults beneath them, iioors withchambers below them, and bridges, and also girders employed in suchstructures-are subject to transverse 'strain caused by loads on theirtop, and have to resist compression of their upper halves above theircentral neutralline and tension or strain below their neutral line orplane,the neutral line, which liesin the central horizontal plane of thebody or structure, being the dividing linebetween the two opposingforces. In order to illustrate the action of these two opposing forces,I have shown in Fig. 1 a longitudinal vertical'sectie'ial view ofabridge, sidewalk, or similar structure supported on end supports, as itappears before any weight or-load is rested upon it; and in Fig. 2 Ihave shown the same structure deflected bythe weight of a load, L, theimaginary vertical parallel lines e f e f in Fig. 1 being changed whenthe structure is deflected intoradial lines, as shown in Fig. 2, xyinboth views rep- ICO IIO

gradually increases until the top surface is reached, where thecompression is the greatest. The bottom,measured ovei` its length,hasbecomed 'lengthened and the top shortened. The cement, concrete,artificial stone, or similar material having great power of resistingcompression, the part above the neutral line x 1/ will strongly resistthe weight of the load from lessening the distance between theimagi:nary lines e e at the top of the structure, and the material unaide'dwill thus in its upper part resist a heavy load; but havingcomparatively little power of' resisting strain or tension, and beingthus weak below the neutral line am, it is evident that if the distancebetween theimaginary linesff is to be prevented from increasing underthe weight of a load the strength of the structure should be computed inaccord with its great power to resist zompression.

Girders, bridges, and similar structures are now constructed with largemetallic beams extending in their vertical height nearly to the top ofthe girder or structure, and adapted to carry the entire load byresisting both the compressive force and the tensile strain. I greatlylessen the expense andat the same time add to the strength of the girderor structure by embedding in the lower part of the girder or structureb, below the neutral line thereof', a small I-shaped metallic beam orbeams, a, of about onehalf the height of the large beam now employed,and consequently only about one-half as expensive. This beam is cementedin the material in which it is embedded, (by any suitable cement, or bythe material itself when the latter is cement, provided itis of greatadhering quality, hydraulic cement being` preferred,) which surroundsthe beam and prevents the surrounding material slipping or sliding overit when the girder or structure is deflected by a weight, being thuspractically integral with the body in which it is embedded. By thisarrangement the small I-shaped beam p strengthens the girder orstructure most effectively against strain or tension, as it is entirelybelow the neutral line of the body, and therefore its entire strength isutilized to resist the tensile strain. At the same time that part of thematerial above its neutral plane or line serves effectively to resistthe compressive force, my improved construction' thus Vutilizingthematerial of the body or structure itself to resist the compressiveforeei'A small metallic Ishaped beam, as I have applied it, has al largesurface for the material to adhere to, and is of a `form that with alcomparatively small quantity offmetal strongly resists bending to afargreater extent than a beam of square, round, or iat crosssection couldpossibly do, if containing only the same amount of metal. These beamsmay have two or more fianges; but when formed with only one this isalways on top, so that the material of the body can extend under theflange on each side of the beam.

When desired, resistance-plates d .may be bolted or otherwise rigidlysecure positions to the beam, or to a flat b of its ends, as shown inFigs. 8 z sist in preventing the extension of the material b below itsneut the beam was not cemented, or w; Without being cemented and witsistance-plates, when the bridge was considerably deflected under z as Lin 0,111@ learn would b above its neutral line g h to the tent at itstop, while the structui ening below its neutral line my w01 the beam, asshown in Fig. 9,

beam, instead of strengthening th would, in fact, tend rather to we willbe seen that the resistancewhen applied to a fiangeless uncel willstrengthen thestrueture by the material from slipping over making thebeam practically an i1 of the girder or structure.

When two or more of the smal embedded parallel to each other in urebelow its neutral line, as sho` 10,11, 12, 13, and 14C, and a weigh! thestructure between any of the deflects that arch or part of" the stdirection of the thrust against the of the beams is changed to a sligl:angle, as indicated by the dotted l: rows in Figs. 10 and 11, thus thmaterial under the taper flanges ol which ,fectively prevents the m:slipping over the beams. The beai be placed parallel to one another lintegral or solid structure, as `sl1o 10 and 1l, the left-hand portionof Fig. 14, or may be embedded inl of the supporting-divisions ofstructure, as shown in the rigltshz of Figs. 12 and 13.

When, as in Figs. 12, 13, and 14 flanged beams embedded 'in thestructure are supported at their e longitudinal ties d', to which thebolted, and the crowns of the arche structure is either whole or sectiornected and braced to the longit by the struts or braces b, e, T, an(lform 'the subjectmatter` of a separ: tion, and which I will not,therefo; here at length,) the tensile strain both in direct and crossdireeti( cement, concrete, articial stone, cement or mortar,- lor-bother likt above t i neutral line, yresist the c force also bothindireetwandcross Having thus described my invei I claim, and desire tosecure by Letl 1s- 1. The combination, with a gir floor, or other bodyof cement, con ficial stone, or similar material, metallic Ishaped beamor beams e1 the lower part ofthe body below t line thereof to resist thetensile s tructnre is deflected by the Weight vnd thematerxii thrustagainst the mgesof a beam,to prevent the slipne material, substantiallyras deombination, with a girder, bridge, her body ol cement, concrete,arti- 5, or similar material, of a small haped beam or beams embeddedand n the lower part of the body below ,line thereof to resist thetensile when the structure is deflected by of a load and the materialthrust l web and the 'flanges of a beam, to e slippage of the material,substanscribed.

:ombinatiom with a girder, bridge, her body oi'eement, concrete, artie,or similar material, of a flanged am or beams or flanged bar or barsupright'resistance-plate secured to a of its ends and embedded in the ofthe body below the neutral line ombination, with bridge, floor, orleture builtin arches and composed concrete, artificial stone, orsimilar i' lsmall flanged metallic beams emand cemented in the structurebelow the neutral line thereof and parallel to one anotherin ahorizontal plane, and longitudinal non-embedded ties supporting andhaving secured to them the ends ol' said embedded ties.

6. The eombination,with abridge, sidewalk, iloor, or like structurecomposed of cement, concrete, or like material, and constructed intlator arched sections or divisions, of small flanged metallic beams orbars having end resistance-plates embedded and cemented in thesupporting-sections below the neutral line thereof, and the longitudinalnon-embodded ties supporting and having secured to them the ends of saidembedded ties.

PETER H. JACKSON.

Witnesses:

JAMES B. LANE, HENRY- HAUsTEIN,

